Value of MRI in Brain Ring enhancing lesions

Abstract

Objectives : to evaluate the role of contrast enhanced MRI to distinguish the ring enhancing brain lesions with histological findings and clinical diagnosis as reference standard

Methodology: This prospective study was done in may 2011 to may 2012. 20 patients with various ring enhancing lesions in the brain detected by MRI with different clinical conditions, fifteen males and 5 females between 13-63 years age MR imaging was performed with MRI of (Philips - achiva 1.5 Tesla 16 channels). Routine sequences of T1, T2 and FLAIR spin echo sequences with IV contrast, gadolinium were carried out. Statically analysis include sensitivity, specificity and accuracy accounting in this study

Results : Contrast enhanced MRI revealed 4 cases of non neoplastic and 13 cases as neoplastic brain ring lesions compared with histopathology which revealed 5 cases of non neoplastic and 15 cases of neoplastic brain ring enhancing lesions. Sensitivity of MRI for non neoplastic lesions was 80% and specificity is 86.6%. Sensitivity of MRI for neoplastic lesions was 86.6% and specificity was  80%. Accuracy of MRI in differentiation of ring enhancing brain lesion either neoplastic or non neoplastic was 85%. MRI of neoplastic ring lesions revealed 4 cases as metastasis and 9 cases as primary tumor of high grade astrocytoma (globlastoma multiforme ) while histopathology reveal 5 cases metastasis and 10 cases glioblastoma multiforme. Sensitivity of MRI for metastatic ring lesion was 80% and specificity was 81.8%. Sensitivity of MRI for primary neoplastic tumor is 81.8% and specificity was 66.6%. MRI for non neoplastic ring lesions included 3 cases as abscess, on case resolving hematoma while histopathology revealed 5 cases of non neoplastic ring lesions, 3 cases pyogenic abscess, one case resolving hematoma and one case radiation necrosis

Conclusion and recommendation: The accuracy of differentiation of the neoplastic of non neoplastic ring enhancing lesions by MRI is 85%. In doubtful cases diagnosis improved by use of further sequences like diffusion- perfusion studies and nuclear studies.